Package org.jline.utils

Class DiffHelper

java.lang.Object

org.jline.utils.DiffHelper

public class DiffHelper
extends Object

Utility class for computing differences between strings with ANSI attribute awareness.

The DiffHelper class provides methods for computing the differences between two strings while being aware of ANSI escape sequences and text attributes. This allows for proper diffing of styled text without breaking the ANSI escape sequences.

Unlike standard diff algorithms, this implementation ensures that any text in a Diff object is a valid ANSI string with properly balanced escape sequences. This is particularly important when diffing AttributedStrings or other text with embedded styling information.

The diff algorithm identifies three types of operations:

• DELETE - Text that exists in the first string but not in the second
• INSERT - Text that exists in the second string but not in the first
• EQUAL - Text that is common to both strings

This class is particularly useful for implementing features like change highlighting in terminal applications, where differences between versions of text need to be displayed with proper styling.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	DiffHelper.Diff	Class representing one diff operation.
static enum	DiffHelper.Operation	The data structure representing a diff is a Linked list of Diff objects: {Diff(Operation.DELETE, "Hello"), Diff(Operation.INSERT, "Goodbye"), Diff(Operation.EQUAL, " world.")}

Constructor Summary

Constructors

Constructor	Description
DiffHelper()

Method Summary

Modifier and Type	Method	Description
static List<DiffHelper.Diff>	diff(AttributedString text1, AttributedString text2)	Compute a list of difference between two lines.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

DiffHelper

public DiffHelper()

Method Details

diff

public static List<DiffHelper.Diff> diff(AttributedString text1,
 AttributedString text2)

Compute a list of difference between two lines. The result will contain at most 4 Diff objects, as the method aims to return the common prefix, inserted text, deleted text and common suffix. The computation is done on characters and their attributes expressed as ansi sequences.

Parameters:

text1 - the old line

text2 - the new line

Returns:

a list of Diff